Kaolin is a fine usually white clay formed by the weathering of aluminous minerals (as feldspar) and mainly consists of kaolinite. Kaolinite is commonly represented by one or more of the chemical formulae Al4Si4O10(OH)8; Al2O3.2SiO2.2H2O; and/or Al2Si2O5(OH)4. Kaolin is one of the many industrial minerals mined today. Reserves are found in Georgia (USA), Egypt, Brazil, United Kingdom, Queensland (Australia), Korea, and Ukraine.
The mining of many industrial minerals in China is rapidly increasing. Kaolin is among these industrial minerals. Kaolin deposits exist in the Shanxi province of China. However, Shanxi kaolin may differ from kaolin found in other parts of the world.
Generally speaking, kaolin from different countries, and even different deposits within the same country, differs in many respects due to variations in a number of kaolinite properties. Examples of such properties include degree of crystallinity, particle size, particle shape, size and/or shape distribution.
Variations in properties lead to differences in performance of the resultant kaolin products. For example, crystallinity impacts resultant brightness, whiteness, opacity, gloss, and viscosity of the resultant products. Particle size, shape, and distribution impacts the smoothness, optical properties, and flow properties of the resultant products.
The greatest demand for kaolin based products comes from the paper industry, which uses them to coat and fill papers and boards. However, kaolin based products include paints, agricultural compositions, fiberglass products, polymer and rubber compositions, ceramic applications, catalyst supports, pharmaceuticals, cosmetics and personal care applications such as facial masks and body masks, electrical components, adhesives, filter aids, and many more. Improved processing of kaolin and improved kaolin products are likely to provide improved products that contain or employ kaolin.